The proposed Carmichael mine and infrastructure program is believed to be worth between $16.5 billion and $21 billion and to provide 10,000 jobs compared with Deloitte’s estimate of 64,000 jobs generated by the Reef, according to the report. 

However, Frydenberg underplayed the impact of the Carmichael mine. 

He said Adani's planned mine was "300km inland ... in a dry, dusty part of Queensland" and if Australia did not help meet India's energy needs, another country would – with dirtier coal – and reap all the economic benefits.

"If Australia vacates this field, not only will we be forgoing billions of dollars' worth of export income and thousands of jobs domestically, but somebody else will sell that coal into India and the impact on the environment could be worse in terms of emissions," Frydenberg said.

The Australian Conservation Foundation said emissions from the coal Adani would mine would fuel the primary threat to the Barrier Reef's survival: warming of the ocean through climate change.

"It's just a disturbing statement to hear from our federal environment minister," ACF campaigner Basha Stasak told AAP.

"Our governments seem to refuse to acknowledge the reality of the situation. It's a choice – it's coal or it's coral and we are going to have to pick."